Screw conveyer.



No. 7|o,a79. =Patenten oct. 7, |9n2.- .1. A. MITGHELL. SCREW CONVEYER.

(Application filed Apr. 26, 1902.1) (lo Moxie-l.)

UNTTnD STaTns PATENT OFFICE.

JOSEPH A. MITCHELL, OF BROOKLYN, NEW YORK.

SCREW CONVEYER.

SPECIFICATION forming part of Letters Patent No. 710,879, dated October '7, 1902.

Application filed April 26, 1902. Serial No. 104,784. (No model.)

To r//ZZ wle/0m, it 71u03/ concern:

Be it known that I, JOSEPH A. MITCHELL, a citizen of the United States, and a resident of the city of New York, borough of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Screw Oonveyer, of which the following is a full,

clear, and exact description.

The object of this invention is to provide a screw conveyer which will he capable of receiving material along its entire length and of uniformly advancing all of the material received. If an ordinary screw is placed in a conveyei-trongh and material fed to it along its entire length, the mass of material gathcred by the screw is rolled entirely around and the screw discharges no more in a given period of revolution than would be discharged in the same period were the material fed merely for a distance along the screw equal to the pitch thereof-that is to say, the longitudinal distance between one turn of its blade. By means of-my invention, however, the screw may be fed along its entire length, and owing to the peculiar form ofthe screw it will discharge-say, for example, in one revolutionan amount of material equal to that received by it during such revolution.

This specification is an exact description of one example of my invention, while the claims define the actual scope thereof.

Reference is to he had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure l is a plan view of the invention. Fig. 2 is a longitudinal section thereof, and Fig. 3 is a section on the line 3 3 of Fig. 2.

a indicates the trough of the screw, which is open at its upper side throughout its length and which is gradually enlarged or flared from its receiving toits discharge end, and at the discharge end an orifice a is formed to permit the material to pass out. In the ends of the trough a are placed boxes u?, which carry the journals b of the screw.

l) indicates the core of the screw, and this core is tapered gradually from the receiving to the discharge end of the trough, the core being largest at the receiving end of the conveyer and tapering into-nearly the thickness of the journals at the discharge end. On this core Z) is placed the thread b2 of the screw. The thread increases in height `or radius steadily from the receiving to the discharge end of the screw not only to compensate for the dilference in the diameter or taper of the core b, but also to make the diameter of the screw greater at the discharge than at the receiving end, as is `illustrated in Figs. l and 2. The trough a is liared toward the receiving end, so as to accommodate this increase in diameter or Aflare of the screw. It will be observed, therefore, that the increase in the height or radius of the blade h2 is not only proportioned to the increase in diameter of the core, but is even greater in proportion, so that the exterior form of the screw gives it a dare or gradual increase in diameter toward the receiving end.

It may be observed in connection with the screw thus constructed that material may be fed into the top of the trough a throughout its entire length and that the screw will steadily clear itself and advance through the discharge-orifice a all of r the material fed into the trough. Such an apparatus placed in the bottom of the hopper will feed the material out of the same much more rapidly than a screw of the ordinary construction.

Having thus described my invention, I claim as new and desire to secure hy Letters Patentl. In a conveyer the combination of a screw comprising a core tapered toward the discharge end, and a blade or thread gradually increased in height or radius toward the discharge end, and a trough conforming to the form of the screw and open at the top through out the length thereof, said trough receiving the screw.

2. A conveyer-screw, comprising a core tapered toward the discharge end, and a blade or thread gradually increased in height or radius toward the discharge end, said increase in the height or radius of the blade or thread being sufficient to give the exterior form of the screw a flare or increase of diameter toward its discharge end.

3. In a conveyer the combination of a screw comprising a core tapered toward the Vdischarge end, and a blade or thread gradually increased in height or radius toward the discharge end, said increase in the height or ran ICO dius of the blade or thread being sufficient to give the exterior form of the screw a iiare or increase of diameter toward its discharge end, and a trough in which said screw is placed, the trough conforming to the forln of the screw and being open at its top throughout the length thereof.

4. A cOnVeyer-screw, comprising a core ltapered toward the discharge end, a blade or thread gradually increased in height or radius toward the discharge end, said increase in the height or radius of the blade or thread being suilicient to give the exterior form of the screw a flare or increase of diameter toward its discharge end, and a trough in which said screw is placed, the trough conforming to the form ofthe screw and being open at its top through- In testimony whereof I have signed myl name to this specification in the presence of two subscribing Witnesses.

lJOSEPH A. MITCHELL.

XVitnesses:

ISAAC B. OWENS, JNO. M. RITTER'. 

